The present disclosure relates to a vehicle drive device including an oil passage that supplies oil discharged by a hydraulic pump, which suctions oil from an oil storing portion, to a rotary electric machine as cooling oil, and an oil passage that returns the oil supplied to the rotary electric machine to the oil storing portion.
Japanese Patent Application Publication No. 2010-190425 discloses a configuration in which a clutch chamber [5] is disposed on the vehicle front side of a transmission chamber [4], and oil is returned from the clutch chamber [5] to the transmission chamber [4] through an oil passage opening [8] formed in an intermediate wall [6] disposed between the clutch chamber [5] and the transmission chamber [4], Further, in the configuration disclosed in Japanese Patent Application Publication No. 2010-190425, in order to reduce the amount of oil that flows back from the transmission chamber [4] to the clutch chamber [5] during sudden braking of the vehicle, a flap valve [9] that allows the flow of oil to the transmission chamber [4] and blocks or interferes with the flow of oil to the clutch chamber [5] is provided at the oil passage opening [8]. Japanese Patent Application Publication No. 04-219561 discloses a valve body [26a] that is similar to the flap valve [9] of Japanese Patent Application Publication No. 2010-190425 although the direction in which oil is allowed to flow is opposite to that of Japanese Patent Application Publication No. 2010-190425 in the vehicle front-rear direction.
In the configuration of Japanese Patent Application Publication No. 2010-190425, due to the positional relationship between a pivot axis [10] of the flap valve [9] and a stopper [12], not only during braking of the vehicle but also during normal travel (for example, when the vehicle is traveling straight at a constant speed), the flap valve [9] opens the oil passage opening [8] with a pressing force toward the vehicle rear side which is applied to the flap valve [9] by the oil flowing from the clutch chamber [5] to the transmission chamber [4], so that oil is returned to the transmission chamber [4]. That is, the flow of oil toward the transmission chamber [4] is interfered with by the amount of the pressing force that presses the flap valve [9]. For example, when the vehicle is traveling on a descending slope, a force in the direction of closing the oil passage opening [8] is applied to the flap valve [9] due to gravitational acceleration, so that the flap valve [9] is not easily opened, which makes this issue more prominent. However, this issue is not particularly recognized in Japanese Patent Application Publication No. 2010-190425.
Further, Japanese Patent Application Publication No. 2013-95389 discloses a vehicle drive device including a first oil passage that supplies oil discharged by a hydraulic pump, which suctions oil from an oil storing portion, to a speed change device as hydraulic oil, a second oil passage that supplies the oil discharged by the hydraulic pump to a rotary electric machine as a cooling oil, and a third oil passage that returns the oil supplied to the rotary electric machine to the oil storing portion. In the configuration of Japanese Patent Application Publication No. 2013-95389, a discharge oil passage [AD] that returns the oil supplied to the rotary electric machine [MG] to a first oil storing portion [U1] is provided as the third oil passage, and a flow restricting mechanism [100] for reducing the amount of oil that flows back through the discharge oil passage [AD] during sudden braking of the vehicle is provided. Referring to paragraph 0076 in Japanese Patent Application Publication No. 2013-95389 and FIG. 5, etc., the flow restricting mechanism [100] for reducing the amount of oil that flows back through the discharge oil passage [AD] is formed with a structure in which a second opening portion [AEo] on the upstream side of the discharge oil passage [AD] is located above a first opening portion [ADo] on the downstream side. In the configuration disclosed in Japanese Patent Application Publication No. 2013-95389, in order to enhance the effect of reducing back flow of oil, a valve [6] that switches from a closed state to an open state in accordance with a hydraulic pressure from the side opposite to the first oil storing portion [U1] is provided as the flow restricting mechanism [100] in the discharge oil passage [AD] as illustrated in FIG. 7 of Japanese Patent Application Publication No. 2013-95389. However, in this configuration, as in the configuration of Japanese Patent Application Publication No. 2010-190425, not only during braking of the vehicle but also during normal travel, the oil flow to the first oil storing portion [U1] through the third oil passage is interfered with.